Objective: The Purpose Of this Study was to determine plasma malondialdehyde (MDA), superoxide dismutase (SOD), soluble E-selectin (sE-selectin), fibronectin, endothefin-1 (ET-1) and nitric oxide (NO) levels in women with preeclampsia and to find out the relations of diastolic blood pressure with these variables. Study design: We performed a case-control study consisting of randomly selected 34 healthy pregnant women and 35 patients diagnosed as preeclampsia. Lipoperoxidation was ascertained by the formation of MDA. SOD activity was determined by the method Of Sun et al. Plasma concentration of NO was estimated using, colorimetric assay. Plasma ET-1 and sE-selectin were measured by enzyme-linked immunosorbent assay (ELISA). A nephelometric method for fibronectin quantitation was used. Results: The mean plasma level of MDA was significantly higher and SOD was significantly lower in preeclamptic pregnancies (P < 0.001). Plasma concentrations of fibronectin, sE-selectin and ET-1 were significantly increased, whereas NO was significantly decreased in women with preeclampsia than norinotensive wonien (P < 0.001) Conclusion: Increased plasma levels of MDA, fibronectin, sE-selectin, ET-1, and decreased plasma levels of NO and SOD in preeclamptic patients suggest that poorly perfused fetoplacental unit is the origin of oxygen free radicals and lipid peroxides. (C) Elsevier Ireland Ltd. All rights reserved.